Results for: "OptionParser"

Changes asynchronous interrupt timing.

interrupt means asynchronous event and corresponding procedure by Thread#raise, Thread#kill, signal trap (not supported yet) and main thread termination (if main thread terminates, then all other thread will be killed).

The given hash has pairs like ExceptionClass => :TimingSymbol. Where the ExceptionClass is the interrupt handled by the given block. The TimingSymbol can be one of the following symbols:

:immediate

Invoke interrupts immediately.

:on_blocking

Invoke interrupts while BlockingOperation.

:never

Never invoke all interrupts.

BlockingOperation means that the operation will block the calling thread, such as read and write. On CRuby implementation, BlockingOperation is any operation executed without GVL.

Masked asynchronous interrupts are delayed until they are enabled. This method is similar to sigprocmask(3).

NOTE

Asynchronous interrupts are difficult to use.

If you need to communicate between threads, please consider to use another way such as Queue.

Or use them with deep understanding about this method.

Usage

In this example, we can guard from Thread#raise exceptions.

Using the :never TimingSymbol the RuntimeError exception will always be ignored in the first block of the main thread. In the second ::handle_interrupt block we can purposefully handle RuntimeError exceptions.

th = Thread.new do
  Thread.handle_interrupt(RuntimeError => :never) {
    begin
      # You can write resource allocation code safely.
      Thread.handle_interrupt(RuntimeError => :immediate) {
        # ...
      }
    ensure
      # You can write resource deallocation code safely.
    end
  }
end
Thread.pass
# ...
th.raise "stop"

While we are ignoring the RuntimeError exception, it’s safe to write our resource allocation code. Then, the ensure block is where we can safely deallocate your resources.

Guarding from Timeout::Error

In the next example, we will guard from the Timeout::Error exception. This will help prevent from leaking resources when Timeout::Error exceptions occur during normal ensure clause. For this example we use the help of the standard library Timeout, from lib/timeout.rb

require 'timeout'
Thread.handle_interrupt(Timeout::Error => :never) {
  timeout(10){
    # Timeout::Error doesn't occur here
    Thread.handle_interrupt(Timeout::Error => :on_blocking) {
      # possible to be killed by Timeout::Error
      # while blocking operation
    }
    # Timeout::Error doesn't occur here
  }
}

In the first part of the timeout block, we can rely on Timeout::Error being ignored. Then in the Timeout::Error => :on_blocking block, any operation that will block the calling thread is susceptible to a Timeout::Error exception being raised.

Stack control settings

It’s possible to stack multiple levels of ::handle_interrupt blocks in order to control more than one ExceptionClass and TimingSymbol at a time.

Thread.handle_interrupt(FooError => :never) {
  Thread.handle_interrupt(BarError => :never) {
     # FooError and BarError are prohibited.
  }
}

Inheritance with ExceptionClass

All exceptions inherited from the ExceptionClass parameter will be considered.

Thread.handle_interrupt(Exception => :never) {
  # all exceptions inherited from Exception are prohibited.
}

Returns whether or not the asynchronous queue is empty.

Since Thread::handle_interrupt can be used to defer asynchronous events, this method can be used to determine if there are any deferred events.

If you find this method returns true, then you may finish :never blocks.

For example, the following method processes deferred asynchronous events immediately.

def Thread.kick_interrupt_immediately
  Thread.handle_interrupt(Object => :immediate) {
    Thread.pass
  }
end

If error is given, then check only for error type deferred events.

Usage

th = Thread.new{
  Thread.handle_interrupt(RuntimeError => :on_blocking){
    while true
      ...
      # reach safe point to invoke interrupt
      if Thread.pending_interrupt?
        Thread.handle_interrupt(Object => :immediate){}
      end
      ...
    end
  }
}
...
th.raise # stop thread

This example can also be written as the following, which you should use to avoid asynchronous interrupts.

flag = true
th = Thread.new{
  Thread.handle_interrupt(RuntimeError => :on_blocking){
    while true
      ...
      # reach safe point to invoke interrupt
      break if flag == false
      ...
    end
  }
}
...
flag = false # stop thread

Returns whether or not the asynchronous queue is empty for the target thread.

If error is given, then check only for error type deferred events.

See ::pending_interrupt? for more information.

Recursively calls passed Proc if the parsed data structure is an Array or Hash

Insert text into the line at the current cursor position.

See GNU Readline’s rl_insert_text function.

Raises NotImplementedError if the using readline library does not support.

Returns true if the contents of a file A and a file B are identical.

FileUtils.compare_file('somefile', 'somefile')  #=> true
FileUtils.compare_file('/bin/cp', '/bin/mv')    #=> maybe false

Returns true if the contents of a file A and a file B are identical.

FileUtils.compare_file('somefile', 'somefile')  #=> true
FileUtils.compare_file('/bin/cp', '/bin/mv')    #=> maybe false

Returns true if the contents of a stream a and b are identical.

Returns true if the contents of a stream a and b are identical.

Enters exclusive section.

Enters exclusive section and executes the block. Leaves the exclusive section automatically when the block exits. See example under MonitorMixin.

Initializes the MonitorMixin after being included in a class or when an object has been extended with the MonitorMixin

Reset the dir and path values. The next time dir or path is requested, the values will be calculated from scratch. This is mainly used by the unit tests to provide test isolation.

Glob pattern for require-able path suffixes.

Use the home and paths values for Gem.dir and Gem.path. Used mainly by the unit tests to provide environment isolation.

The home directory for the user.

Path for gems in the user’s home directory

Adds a response handler. For example, to detect when the server sends a new EXISTS response (which normally indicates new messages being added to the mailbox), add the following handler after selecting the mailbox:

imap.add_response_handler { |resp|
  if resp.kind_of?(Net::IMAP::UntaggedResponse) and resp.name == "EXISTS"
    puts "Mailbox now has #{resp.data} messages"
  end
}

Removes the response handler.